The present invention relates to a circuit for transferring data from a control device to a plurality of driver devices disposed in, for example, the printing head of a printer.
The driver devices in question typically have shift registers through which the data are transferred in synchronization with a clock signal. The clock signal is conventionally supplied to the first driver device through an interface cable, then propagated from one driver device to the next, with amplification and reshaping by buffer circuits in each driver device.
Due to the increasing printing speeds of recent printers, the conventional scheme has begun to encounter a number of problems. Briefly, the transfer of a high-frequency clock signal through the interface cable generates unwanted electromagnetic interference (EMI); propagation delays in the buffer circuits become a limiting factor on printing speed; and the clock signal becomes increasingly susceptible to disruption by switching noise. These problems will be described in more detail later.